How much calcium is too much?

Q: How much calcium is too much? I take 1,500 mg/day, and my doctor wants me to add another 500 mg for my thinning bones. I drink milk and wonder if I may be overdosing.

A: Too much calcium (2,000 mg/day) can lead to "milk-alkali syndrome." The extra supplement might make you vulnerable to this complication, which increases the risk of bone fractures and kidney stones.

Q: Can Preparation H raise blood pressure? I have been using Preparation H for a few weeks for a hemorrhoid problem. During that time, it seems that my blood pressure has been going up.

I noticed that in the Prep H warning it mentions to ask your doctor before using it if you have high blood pressure.

A: One of the active ingredients in Preparation H is phenylephrine, a vasoconstrictor. Vasoconstrictors work by contracting blood vessels and shrinking swollen tissues. One possible side effect is increased blood pressure.

The rectum is well-supplied with blood vessels. That is why suppositories are effective for delivering drugs into the bloodstream. When phenylephrine is absorbed from these tissues, it may raise blood pressure.

Q: Are there vitamins or herbs that a person can take instead of a prescription drug for high blood pressure? I've heard about garlic. Is there anything else?

A: The newest candidate for natural blood-pressure control is beet juice. A study in the journal Hypertension (online Feb. 4, 2008) showed that two cups (500 ml) of beet juice lowered blood pressure by approximately 10 points. That is better than many prescription drugs. The effect lasts up to 24 hours.

Beets are high in dietary nitrate and increase the amount of nitric oxide in the body. Nitric oxide (NO) helps blood vessels relax, lowering blood pressure. NO has anti-inflammatory activity and discourages blood-clot formation.

A diet rich in vegetables and even dark chocolate also can lower blood pressure. Pomegranate and grape juice, magnesium supplements and breathing exercises can be beneficial.

Q: I have found that Activia yogurt is excellent for stopping flatus. Two other friends tried it, and they were pleased with the results, too.

A: Activia yogurt from Dannon contains live beneficial bacteria called Bifidus regularis. When such probiotic bacteria are included in yogurt, they help digest the milk sugar lactose. People who can't break lactose down in the gut often suffer flatulence, so perhaps that is the explanation for your unexpected benefit.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them c/o King Features Syndicate, 888 Seventh Ave., New York, NY 10019, or via their Web site: www.peoplespharmacy.org